1. Field of the Invention
The present invention relates to novel ampholytic ter-polymers, personal care compositions containing said ter-polymers and methods for using such ter-polymers. The herein described ampholytic ter-polymers comprise at least an ethylenically unsaturated cationic monomer, a monomer containing a carboxylic acid or sulfonic acid group and a diallyamine or diallyamine derivative. The ter-polymers and ter-polymer compositions of the present invention are useful in the treatment of keratin-containing substrates. Keratin substrates include, but are not limited to, animal and human hair, skin and nails.
Hair is composed of keratin, a sulfur-containing fibrous protein. The isoelectric point of keratin, and more specifically of hair, is generally in the pH range of 3.2-4.0. Therefore, at the pH of a typical shampoo, hair carries a net negative charge. Consequently, cationic polymers have long been used as conditioners in shampoo formulations, or as a separate conditioning treatment to improve the wet and dry combability of the hair. The substantivity of the cationic polymers for negatively charged hair along with film formation facilitates detangling during wet hair combing and a reduction in static flyaway during dry hair combing. Cationic polymers generally also impart softness and suppleness to hair.
Although cationic polymers and amphoteric polymers have long been used as conditioners in personal care compositions such as shampoos and bodywashes, the commercially available polymers are deficient in providing a certain combination of effects on keratinic substrates. For instance, a certain number of claims related to cationic and amphoteric polymers described in the literature focus, either on a limited number of attributes for the conditioning process such as friction reduction and softness, or on the ability of the polymers to act as deposition aids for silicone only. These type of polymers are disclosed in U.S. Pat. Nos. 5,573,709, 5,977,038, 6,200,554, 6,451,298, 5,302,322, 6,348,188 B1, EP 0 529 883 B1, and U.S. Application Publication Nos. 2006/0123564 and 2005/0002871 herein incorporated entirely by reference.
The shortcomings in the performance of current commercial conditioning polymers have prompted the search for new polymeric materials that will make possible the achievement of a true “2 in 1” conditioning shampoo. Thus, in the area of hair and skin care in particular, there is a need for cationic polymers that will display simultaneously the following characteristics: 1) They should be able to act as deposition aids not only for silicone but also for a wide range of other conditioning actives on keratinic substrates, 2) The polymers should be able to provide by themselves basic conditioning effects to keratinic substrates without the need of any additional conditioning ingredient, and 3) They should be capable of interacting with other conditioning actives to provide conditioning synergies leading to additional and novel conditioning functionalities, i.e. refatting of hair/skin, elimination of hair “squeakiness” after washing, reduced irritation, improved emolliency, softness, wet and dry friction reduction and shine.
The achievement of these three effects with one single cationic polymer poses, however, major technical challenges. This is especially true in “2 in 1” washing or cleansing compositions where the processes of cleansing and deposition are antagonistic in nature; i.e. the cleansing process not only will tend to remove the polymer from the keratinic substrate but also any other conditioner material that deposits on its surface.
The present inventors have successfully designed amphoteric ter-polymers that are able to perform the three tasks described above without affecting the washing process. While not wishing to be bound by theory, it is believed each monomer unit in the ter-polymer backbone has a specific functionality. For instance, the cationic moieties in the ter-polymer are substantive to negative keratinic substrates from the washing compositions, and in addition allow complexation with anionic surfactants. Furthermore, complexation of the ter-polymer with other conditioning materials such as fatty amines and cationic surfactants is achieved by the presence of an anionic monomer unit. Finally, a certain degree of hydrophobicity and polarity for conditioning and moisturization is attained with a third monomer unit formed from diallyamine or derivatives of diallyamine.
With the above described monomer composition the ter-polymer can also form in situ coacervate complexes with the washing composition. These complexes have the appropriate rheology to deposit lubricious layers of ter-polymer/surfactant that aid in the deposition of conditioning actives by flocculation. With these characteristics, when the ampholytic ter-polymers are formulated into washing and rinse-off compositions they have the following properties: 1) The amphoteric ter-polymers of the invention have a strong affinity for keratin substrates even in the presence of anionic surfactants, 2) By being slightly hydrophobic and polar they can provide conditioning on their own, 3) Because of their ability to form simultaneously complexes with anionic, fatty amines, and cationic surfactants they can provide enhanced and added functionalities. For instance, as the ter-polymers are able to deposit layers of polymer/fatty moieties on the keratinic substrates they can also act as refatting agents reducing the effect of “hair squeakiness” characteristic of shampooed hair. This later feature is mostly absent in all polymers used in personal care described so far in the literature.
The use of the ter-polymer in cleansing or washing compositions solves, the precipitation difficulties often encountered when cationic surfactants are added to formulations containing anionic surfactants. 4) Finally, because of their ability to form complex coacervates, the ter-polymers can also act as deposition aids for silicone and other oils when combined with them. Thus, not only do the polymers work effectively as conditioners by themselves on keratinic substrates but also they function as deposition agents for fatty amines, fatty quaternaries, silicone, and other conditioning oils from cleansing and rinse-off compositions providing lubricity, softness, styling manageability, and an overall conditioning synergy to keratinic substrates.
2. Brief Description of the Background Art
Cationic and ampholytic conditioning polymers are known for use in personal care compositions.
Cationic homopolymers are specifically known to have thickening effects on formulations and also to be good as conditioning agents for hair and skin. For example, SALCARE SC 96 is a homopolymer of methacryloylethyl trimethylammonium chloride available from Ciba Corporation, Tarrytown, N.Y. It is a well known as a thickener in personal care compositions.
U.S. Publication Application Nos. 2008/0057016, 2008/0206355, 2005/202984 and U.S. Pat. No. 7,303,744 teach homopolymers of acrylamidopropyltrimethyl ammonium chloride (APTAC) and methacrylamidopropyltrimethyl ammonium chloride (MAPTAC) for use in shampoo formulations.
Cationic copolymers such as SALCARE SC60 (APTAC/acrylamide copolymer) available from Ciba Corporation, Tarrytown, N.Y., are taught for use on hair. For example, U.S. Pat. Nos. 5,543,074, 6,908,889, 6,858,202, 6,696,053 and European Application No. 1 911 778 teach copolymers of cationic monomers and acrylamide in hair formulations.
Amphoteric copolymers are also well known for use on hair. For example, U.S. Pat. Nos. 6,555,101, 6,82,776, 6,511,671, 4,814,101, 6,066,315, 6,110,451, and 5,879,670 teach APTAC-acrylic acid copolymers for use in hair. Several U.S. Published Application Nos. teaching similar copolymers are 2005/0276778, 2003/0086894, 2003/0131424 and 2008/0033129 and Canadian Application No. 2139495. Also cationic celluloses such quaternized hydroxethyl cellulose and cationic guar gum are well known for use in hair.
Further, U.S. Pat. No. 6,348,188 B1, U.S. Pat. No. 6,706,258 B1, and European Application Nos. EP 0 529 883 B1, EP 1 137 397 B1 and EP 0 158 531 B1 teach various cationic polymers capable of depositing silicone on hair.
However, none of these patents or publications teach the inventive amphoteric ter-polymer described herein nor do the above described cationics or amphoterics show the multiple advantages of the present amphoteric ter-polymer. The inventive ter-polymers offer a wider range of conditioning benefits to hair and skin than those previously described in the known art. The ter-polymers are especially useful in 2-in-1 shampoos.